New and interesting (as always) interview with Cullen Bunn, he confirms a supporting cast (like Claremont era) and two-three new members for the group.
http://comicbook.com/2017/03/15/x-men-blue-cullen-bunn/
Briar Raleigh is one of the supporting cast for sure.
The comment of the "time travelers" makes me dream about a time travel to Krakoa to save Petra and Sway and add to the team.